Dry seal pressure type gas holder



NOV. 15, 1955 J, H wlGGlNs ET AL 2,723,908

DRY SEAL PRESSURE TYPE GAS HOLDER Filed MaFCh l5, 1952 2 Sheets-51188121FIG.

FIG. 2.

INVENTORS. JOHN H. WlGG/NS,

L JOHN W. ALLEN,

F. WALTER HORNER,

www

2 Sheets-Sheet 2 Filed March l5, 1952 FIGB.

INVENTORS. JOHN H. WlGG/NS, JOHN W. ALLEN, F. WALTER HORNER,

United States Patent() M DRY SEAL PRESSURE TYPE GAS HOLDER John H.Wiggins, John W. Allen, and Frank Walter Horner, Chicago, Ill.; saidAllen and said Horner assignors to said Wiggins Application March 15,1952, Serial No. 276,730

8 Claims. (Cl. 48-178) This invention relates to dry seal, piston typegas holders and other fluid storage apparatus, of the particular type orkind that comprise a container provided with a cylindrical side wall, avertically movable piston in said container that forms the top wall ofthegas storage space of the apparatus, a seal for the space between thepiston and the containerside wall made of gas tight fabricandconstructed in the form of a flexible curtain suspended between andattached to the piston and to the container side wall and proportionedso as to provide for the rise and fall of the piston, and back upmembers or abutment Vsurfaces disposed in such relationship with saidcurtain like fabric seal 4that during the cycle of operations of thepiston said abutmentvsurfaccs function as back stops that absorbpressure exerted on said seal by the gases confined in the storagechamber of the apparatus. Generally the portion of the container sidewall located above the point where the fabric seal is attached to saidwallv is used' to' constitute an outer back stop that is located at theouter edge of said seal and which absorbs pressures exerted on said sealduring the upward stroke of the piston, and one or more verticallymovable inner back stops or abutment members of tubular or cylindricalform are arranged inside of said outer back stop in spaced, concentricrelation with same so as to absorb pressure exerted on the'fabric sealduring the downward stroke of the piston. If the fabric seal isconstructed in the form of a relatively long or deep cylinder attachedat one of its ends to the outer back stop formed by the container sidewall and attached at its other end to the piston, the inner back stopwill be formed bya tubular or cylindrical member rigidly combined withthe piston and projecting upwardly from same, and if the fabric seal iscomposed of two cylindrical sections one of which is attached to thecontainer side wall and the-other attached to the piston, an additionalvertically movable back vstop of tubular or cylindrical form will bearranged between the piston and the container side wall and attached tosaid two `sections vof the seal in such a way that during the cycle ofoperations of the piston said additional back stopl will coact with theback stop on the piston to back up the inner seal section (the onenearest the piston), and said additional back stop will` coact with theabutment surface on the container side wall to back up the outer sectionof the seal (the one nearest the container wall), as disclosed in U. S.'Patent No. 2,606,824, dated August l2, 1952, to lohn W. Allen. v

Gas holders of the general type or kind above referred to are built forpressures up to inches of water which is' 104 pounds per square foot andthe fabric seals of such gas holders vary in height or depth fromfifteen feet to fifty feet or more. We have found that when the pistonmoves vertically a relatively great distance, there is a tendency forthe fabric seal to move circumferen-V with the inner back stop orabutment surface get larger and larger and finally become converted intoa fold com- 2,723,908 Patented Nov. 15, 1955 ICC posed of threethicknesses of fabric lying one on top of the other in superimposedrelation and pressed tightly against the back stop by the gas pressure.During the upward travel of the piston the fabric seal is progressivelystripped off the inner back stop and progressively applied to the outerback stop and in instances where folds of the kind mentioned have formedin the fabric the layers of the folds remain in superimposed relationeven after the sealhas come in contact with the outer back stop, due tothe fact that the circumferential tension of the fabric is not greatenough to straighten out the fabric and destroy the above mentionedfolds. The result is that the seal is effectively shortened and hencebecomes subjected to strains which stretch it. This process continuesuntil there are enough folds formed with time, that the seal may bestretched until it fails from excessive circumferen-` pressure gasholder of the general type or kind previously i mentioned, which is ofsuch design or construction that destructive wrinkles or folds will notform in the fabric seal whensaid` seal is in contact with the inner backstop or abutment member of the apparatus.

Another object is to provide an eiiicient means of simple design andinexpensive construction` for eliminating circumferential creepage ofthe fabric seal of an apparatus of the general type or kind previouslyreferred to.

Other objects and desirable features of our invention will hereinafterbe pointed out.

We have herein illustrated our invention embodied in a cylindricalabutment member or back stop carried by the piston of a pressure typegas holder whose sealing fabric is constructed in the form of arelatively long or deep cylinder attached at its outer end to the sidewall of the container of the apparatus and attached at its inner end tothe piston adjacent the lower end of the back stop carried by thepistonjbut we wish it to be understood that our invention is applicableto any kind of a back stop or abutment surface employed in a dry sealpressure type gas holder to absorb pressure exerted by the gases on thefabric seal and to assist in controlling the approximate shape vor formof said seal when the apparatus is in use.

Fig.V 1 of the drawings is a fragmentary horizontal sec-r tional viewtaken through the side wall of the container of the apparatus onapproximately the line 1-1 of Fig. 2, looking downwardly onto the upperend of the inner abutment member carried by the piston, the fabric sealbeing omitted so as to more clearly show the shape or form of saidabutment member.

Fig. 2 is a fragmentary elevational view, taken on approximately theline 2"-2 of Fig. 3, looking in the direction indicated by the arrows.

n,P ig. 3 is a fragmentary vertical sectional view showing the containerside wall, the piston, the inner abutment member and thesealin'g'fabric, the point at which aid'iew is taken being indicated bythe line 3-3 of Fig. 4 is an enlarged view of some of the parts shown inFig. 3, illustrating how the fabric seal lies against the fluted orserpentine surface of the inner abutment member carried by the piston,and

Fig. 5 is an enlarged, fragmentary horizontal sectional view, taken onthe line 5-5 of Fig. 2.

In the drawings the referencecharacter 9 designates I said container.The piston B is spaced away from the l container side wall and the spacebetween the piston and said side wall is sealed by a flexible gas tightfabric seal C constructed in the form of cylinder attached s., .as is,assai iii dryl 'ssii presser-je lisljdet's of this general typementioned, rigid back sfd'tis or' aiiitni'nt members are arrangedadjacent the path ofmovfiitiritof -the'fab'ric seal C so' as tocontrol'the shape' or formV of said seal and absorb some of' thepressure exerted by tli 'g'ass on saldseal!Y during the rise and fall ofthe' pistes. y in `tite articulations si ser ittvstitiotrltereittilltistratedthet are tivo Ba'e1sst"f"s or' atnitmetft inertis litersltif' taskittsjtist viiiettgtietit te wit. a" ysitissit'y itis. is sts-A-st sintetica-ist tattiirst tet-tit est: the@ en site areetnisasw'aiaiy fraai trie p veripheralp ortioii` of' sai'n,l`andastationary oacls stop of eyliiidriealpoi tubular' friii'tliat surroundstire ltckstop aiapgd ,iri spaced, concentric rela` tien with tite sans,said statten-ait' naar stjtip'af seitig' formed by the portion of thecontainer sid iall 9 lo`" cated above the point where the seal C isattached io? said wall. When the 'piston is in its lowermost positionthe pressure of the gases in the storage chamber of the apparatuspresses the seal C tightly against the back stop A land during theupward movement of the piston said seal is progressively stripped olfthe inner back stop A siidprossively applied to tite outer' haelt stepA'. pitting tie downward straks si tite pistes the seal c isprogressively stripped slr the outer' back stop A' and' progressively-applied to the inner back stop our` invention ye'onsists iiiconstructing tite inner bask 'stop A iii such a iriarn'el as to' (a)prevnt wrinkles or` folds of niijctiiiil ii front fr'rriing irl these'al o wlieli sata sisal lies against tits inne-t satis stop A; stiatti) prevent the seal C frein creeping `eitstiiitfetetitisityar'oiindthe gas lioldert In this way we eliminate undue circumferentialstretching of tile fabric from which the 'seal C is'y constructed andlthus effectively prevent said seal frptttteafiiigor rupttit'iiiglnrieiiy stated we attain 'these highlydesjifahl results by' providingthe inner haelt stop A with a snsstaiitiairy' tinted, corrugated,scalloped 'or ysinuous shaped seal contacting surface whoseycilfsllirifer'v'eritial le'ngth is substantially the same as thecircumferential length of the surface of ,the outer back stop A.y It isnot essential that the. above mentioned two surfaces be of exactly thesame circumferential length for in some instances we may provide theinner back stop with a sinuous or serpentine's'eal contacting surfacewhose total circumferential length is froml 1% to 2% longer than thecircumferential length of the seal contacting surface of the outer backstop. Accordingly inpthe'specication and claims where we ,refer to theseal contacting surface of the inner back stop or abutment member beingof substantially the, same circumferential length as the seal contactingsurface of the outer back stop or abutment member, we ymean to in-Vclude a structure in which the circumferential length of the iluted;scalloped or serpentine surface of the inner back stop A is either thesame orslightly longer than the length of the seal contacting surface of the `outer back stop A. Sofar as our basic idea is concerned it isimmaterial how they back stop A is constructed so long as the surface ofsame against which therseal is pressed by the gases is provided withraised portions and depressions that increase the circumferential lengthof the portion of said back stop engaged by the seal, and tend to retardcircumferential, creepage ofthe seal. In the form of our inventionherein illustrated the seal contacting surface of the back lstop A iscomposed of ,a series .of ,vertically disposedparallel plates .1 ,ofsubstantially segment shape in horizontal, cross .,sction, arf

ranged with their convexed surfaces presented outwardly` las shown inFig. 1. Said plates 1 are mounted on a.

lti

supporting structure carried; by theV piston B and herein41 illustratedas being composedi of a plurality of vertically-f disposed upriglits 3on the pistonthat carry two horiv z'ntaily' disposed annular shapedmembers 2 to whic'lii thefplate'si are attached, preferablyv in such away that" said plat-es can' li easily detached froni said supportingmn'lirs it and afso adjusted laterally relatively to cach other'. VV@have` herein shown the plates 1f as being clamped to thehorizontalsupporting members'- Z by vertisali'y" disposed clamps 6 at the upperand lower endo of the" each of said clamps 6 being licldin overlappingrcla'rt-i''lnI witht'lre member" 2` which' i"en gages by means of' a"fastening device 7 engaged'vviti's` au'- horizontally disposed crossvpiece 8- that is permanently' attached to the back face or rear side ofthe plate 1,

all as clearly shown in Figs. 2 andi 3';

he'fiuted, corrugated or sinuous shapedl surface of the in'nr bacilli'stop' A is substantially thessarne cumulative lengthcircu-rnferentially as the inside surfacel ofthc'outer track stop Thuswhen the seal C lies on the uted surface of. the' back stop* A there areno wrinkles? in the: se'al,I even though theaverag'e radius of thescalloped orf eurv'edparts of said surfacel is smaller than the radius"f'the cylindrical outer bac'k stop A. We have discovclicdy that tiipreviously mentioned circumferential creep lateral shift f'tlile seal Cis partly due to change in radius, locally, of the outer' hack stop Aand inner back stop A. in order to clearly demonstrate how the scallopedor fluted surface of the back stop A limits or prevents a progressiveand continuing creep of the seal C, we directattentiontov Fig. 5 of thedrawings. Suppose the gas pressure is 20" H 2O or 104# per square foot.The cir.- oulnferential' tension due to radius l is 1/12 ft. 1044# or'8,66# per foot. Now if there is a side creep or laterali shift of theseal so'as to try to create a wrinkle like D, shown in'dottcd lines inFig. 5, then the portion. of the; sea-l in theright hand scallop will beshortened between. pa'kss; s'o thatit is pulled outwardly a little awayfrom the seal contacting' surface of the back stop as indicatedl by' thedotted line E in Fig. 5. If this tries to occur, theradius R3 in Fig. 5becomes immediately many timcsl larger than radius R2 for say 1/s sideshift to the left iri the adjacent scallop. Say radius R3 is sixinches.- Thon it is readily seen that the tension in portion E is656266# per foot or 52# per foot. The result is that the7 seal is pulledback into its proper scallop before it can be pulled out. As soon as acondition tries to move the seall sidewise in the scallop, forces areimmediately set up in an adjacent scallop to prevent that movement. Wealso point out that if a wrinkle such as D in' Fig. 5 should start toform', the pressure of the stored gas sets up forces in the wrinkle Dthat tend to push the extra fabric toward the portion designated E. Thusthe tensionV of E and the push of D, work together to keep the sealproperly in the scallop of the back stop A where it belongs. We preferto make the distance between peaks of the scallops approximately teninches or more, and have the scallops vary in depth from about one inchto about two inches, but of course these dimensions will vary accordingto the sizeof the gas holder. In referring to a liuted, corrugated,scalloped or sinuous shaped surface we mean to include any surface madeup of alternating ridges and valleys disposed vertically orlongitudinally of or parallel to the direction of travel of the piston.

s previously mentioned it is immaterial what means or detail of designis used to obtain or produce the iluted, scalloped, sinuous orcorrugated shape of the surface on the inner back stop A that backs upthe seal C, but one desirable feature of thc particular constructionherein illustrated wherein conveXed or segmental plates are clamped inoperative position on a supporting 'structure carried by the piston,isthe ease with which said plates 1 can be removed for inspectionof the seal. Also with such l ,stniction'it is 'not necessary to bodilyremove all of the plates 1 in order to thoroughly inspect the seal, forafter one of the plates 1 has been bodily removed from the supportingstructure, the clamping devices for the remainder of the plates 1 needonly be loosened sufficiently to permit a plate to be moved laterally inone direction to expose a portion or section of the seal and then movedback to its former position after the inspection has been made, therebyproviding for inspection of the seal around its entire circumferencewith the complete removal and subsequent replacement of only one of theseries of plates 1 that constitute the seal contacting surface of theback stop A.

Having thus described our invention, what we claim and desire to secureby Letters Patent is:

l. In a dry seal pressure type gas holder, the combination of acontainer having a side wall, a vertically movable piston in saidcontainer, a curtain like fabric seal attached to the piston and to thecontainer side wall, and a member adapted to serve as a back stop forsaid seal, provided with a substantially fluted, scalloped, sinuousshaped or corrugated surface against which said seal is pressed by thegases in the storage chamber during the cycle of operations of thepiston.

2. A gas holder of the kind described in claim l in which the ridges andvalleys in the seal contacting surface of said back stop member aredisposed lengthwise of 0r parallel to the direction of travel of thepiston.

3. In a dry seal pressure type gas holder, the combination of acontainer having a side wall, a vertically movable piston in saidcontainer, a sealing means for the piston, at least a portion of whichis formed by a curtain like flexible, gas tight element, and a back stopor abutment member provided with a substantially lluted, scalloped,sinuous shaped or corrugated surface against which said exible elementis adapted to be pressed by the gases confined in the holder.

4. A dry seal pressure type gas holder as set forth in claim 3, in whichthe ridges and valleys of said fluted surface are disposed lengthwise ofthe back stop.

5. In a dry seal pressure type gas holder, the combination of acontainer having a side wall, a vertically reciprocating piston in saidcontainer, a flexible, gas tight fabric element that forms at least aportion of the sealing means for the piston, and two cylindrical shapedabutment sur faces for said fabric element arranged in concentricrelation with each other and with said fabric element interposed betweenthe same, said abutment surfaces being so disposed that one of saidsurfaces backs up said fabric element during the stroke of the piston inone direction and the other abutment surface backs up said fabricelement during the stroke of the piston in the opposite direction, theinnermost abutment surface having alternating ridges and valleys thatextend substantially lengthwise of the direction of travel of thepiston.

6. In a dry seal pressure type gas holder, the combination of acontainer, a vertically movable piston in said container, a sealingmeans for the piston comprising a flexible, gas tight element, andcoacting abutment surfaces made of rigid material and arranged inopposed relation so as to back up said flexible element during the riseand fall of the piston, one of said abutment surfaces beingsubstantially sinuous shaped and having vertically disposed flutes orcorrugations for the purpose described.

7. In a dry seal pressure type gas holder, the combination of avertically reciprocating piston that forms the top wall of the gasstorage chamber of the holder, a sealing means for said pistoncomprising a flexible, curtain like element constructed of gas tightfabric, and two cylindrical concentrically arranged abutment surfacesdisposed in such relationship with each other and with said flexibleelement that the gases in the storage chamber press said flexibleelement into tight engagement with said abutment surfaces during thecycle of operations of the piston, one of said abutment surfaces havingridges and valleys arranged in alternating relationship and disposedsubstantially lengthwise of or parallel to the direction of travel ofthe piston.

8. A dry seal, pressure type gas holder of the kind described in claim7, in which the circumferential length of both of said abutment surfacesis substantially the same.

References Cited in the file of this patent UNITED STATES PATENTS

5. IN A DRY SEAL PRESSURE TYPE GAS HOLDER, THE COMBINATION OF ACONTAINER HAVING A SIDE WALL, A VERTICALLY RECIPELEMENT THAT FORMS ATLEAST A PORTION OF THE SEALING MEANS FOR THE PISTON, AND TWO CYLINDRICALSHAPED ABUTMENT SURFACES FOR SAID FABRIC ELEMENT ARRANGED IN CONCENTRICRELATION WITH EACH OTHER AND WITH SAID FABRIC ELEMENT INTERPOSED BETWEENTHE SAME, SAID ABUTMENT SURFACES BEING SO DISPOSED THAT ONE OF SAIDSURFACES BACKS UP SAID FABRIC ELEMENT DURING THE STROKE OF THE PISTON INONE DIRECTION AND THE OTHER ABUTMENT SURFACE BACKS UP SAID FABRICELEMENT DURING THE STROKE OF THE PISTON IN THE OPPOSITE DIREC-